JPH03103700A - Method and apparatus for removing condensed water from compressed air system - Google Patents

Abstract

PURPOSE: To remove condensed water easily and positively from a compressed air system with atmospheric pressure applied thereto in a resting state by evacuating the compressed air system immediately after energizing positive pressure at least at a time interval, and impeding the mechanical action of at least one load. CONSTITUTION: A control circuit 3 of a dual pump 2 receives starting pulse through a push button switch 6 to put the pump 2 in positive pressure generating operation. After the pump 2 is stopped by a pressure switch 7 in a compressed air system 1, the control circuit 3 puts the pump 2 in negative pressure generating operation over specified time width or until the switch 7 generates a suitable changeover signal. The slight adjusting motion of an adjusting element 5 generated in this case is not a problem, but the compressed air system 1 is evacuated to temporarily generate negative pressure therein, and this negative pressure re-evaporates condensed water. The pump 2 makes vapor flow through in the resting state, and after the pump 2 is finally stopped, the atmosphere enters the evacuated system 1, and the system 1 has atmospheric pressure.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a compressed air system of a motor vehicle which can alternately energize pneumatic pressure and is subjected to atmospheric pressure in a rest state, and particularly to a compressed air system which can also energize negative pressure and Method for removing condensate from a compressed air system for a pneumatic door closing aid having at least one load (compressed air consumer) with mechanical action by pressure activation and device for carrying out this method Regarding.

BACKGROUND OF THE INVENTION Closing devices with pneumatic closing aids for assisting the user in opening and closing motor vehicle doors are already known (German Patent No. 37 10 347 A1).
(see publication). In that case, each reversible pneumatic bomb is energized with positive pressure on the one hand and negative pressure on the other, depending on the direction of transport of the bomb, to assist in closing the door and to assist in opening the door. A single double-acting operating device is attached, which is energized by the motor and has two working chambers for mechanical action in each direction of movement.

The above-mentioned publication does not mention emptying the pneumatic system in the sense of removing condensate, and on the one hand very high positive pressures have to be generated and on the other hand the bomb operating time is limited by the machine. The pneumatic system cannot be emptied due to the limited amount of time required to perform its intended function.

Moreover, the closing aid is activated solely on demand to assist in opening and closing the door.

Compressed air installations with a continuously operated pressure generator having an air storage tank, an air dryer and a regeneration device for this air dryer are known (see DE 32 03 152 Al). The regeneration device of the air dryer uses a venturi nozzle through which an unloaded compressed air flow is passed, in order to increase the pressure difference between the air pressure during the drying process and the regeneration air pressure to improve the regeneration effect. This known air installation, connected by a switching valve on the negative pressure side, has a large number of valves, in order to regenerate the air dryer with reverse flow, only a very small negative pressure is generated in the venturi nozzle to vaporize the condensate. Compressed air from the storage tank must also be used at all times.

In a pneumatic system that is alternately energized by pneumatic pressure and atmospheric pressure, when the water vapor saturation curve of the air at that temperature is exceeded by the positive air pressure, it is common for condensed water to adhere to the inner walls of the system structural components. known to. This is based on the physical fact that air has more water molecules per unit volume at lower pressures than at higher pressures at isothermal conditions. Increasing the system pressure to atmospheric pressure levels does not completely re-vaporize the condensed water in the air present in the system, and further problems arise, at least at temperatures below the freezing point.

Furthermore, washing and drying machines are known in which the drying chamber can be emptied with a water jet bomb in order to evaporate residual moisture (see German Patent No. 33 21 245 A1). This publication does not describe applying positive pressure to the drying chamber or load.

[Problem to be solved by the invention] Starting from a compressed air system of the type mentioned at the outset, it is an object of the invention to develop a system which is alternately energized and deenergized with positive air pressure and is subjected to atmospheric pressure in the rest state. It is an object of the present invention to provide a method that can easily and reliably remove condensed water from water, and also to provide an apparatus for carrying out this method.

SUMMARY OF THE INVENTION According to the invention, this object is achieved in that the compressed air system is emptied immediately after energizing the positive pressure at least at intervals of time, and at least one load is subjected to a mechanical action. This is achieved by not having to do this and by the device according to claims 7 and 8.

[Effect of the invention] When positive pressure is applied to the system, the condensed water that adheres to the inner walls of the system structural components will be rapidly regenerated when negative pressure is applied to the system immediately after positive pressure is applied. It is vaporized. Only after this temporary emptying is the pressure-controlled air system brought to atmospheric pressure in its rest state.

This method is particularly suitable for small-capacity compressed air systems where the load is connected to a positive pressure generator and a negative pressure generator via piping, and there is no need to continuously apply positive pressure. It is suitable, for example, for pneumatic door closing aids in automobiles.

If necessary, the negative pressure of the compressed air system is activated at large time intervals. (if there is a small amount of condensate in a dry atmosphere) or each time a positive pressure is applied.

A device for controlling a dual pump of an electro-pneumatic central locking device of a motor vehicle is also known (see German Patent No. 36 41 276 A1). This known control device drives the dual pump in the opposite direction of rotation at the rated speed after each operating cycle in order to quickly bring the system back to atmospheric pressure level. In such known devices, condensed water does not form in harmful amounts due to the low positive pressure. Apply negative pressure to the system using dual pumps. This is done only in order to initiate an operating process in the direction opposite to the positive pressure energizing direction of the closing/actuating element, so that an undesired operating process does not take place due to negative pressure energizing. Dual pumps must be shut off in a timely manner during reversal operation following positive pressure activation.

Claims 2 to 4 describe advantageous embodiments of the method according to the invention, and claim 7 and claim 13 contain the following:
An advantageous device for carrying out this method is described.

In the case of the device according to the invention, in contrast to the device known from DE 36 41 276 A1, the negative pressure of the dual pump is not employed for the operating process, but merely for drying the air. or used to remove condensed water. Of course, such a measure only makes sense if, by applying the negative pressure, undesired operating processes are not carried out by the operating elements present in the compressed air system.

[Example] The present invention will be explained in detail below with reference to the example shown in the drawings. FIG. 1 shows a simple compressed air system 1 with a dual electric pump 2, its control circuit 3 and a single load 4. The load 4 is, for example, an operating element with an adjusting element 5 for a pneumatic door closing aid in a motor vehicle (not shown). The adjusting element 5 is connected in a not-illustrated manner continuously or only temporarily to the closing member of the door lock or the tailgate lock. When a positive pressure is applied to the operating element by the pressure generator 2, this operating element has a mechanical effect by pressing the closing member by means of the adjusting element 5 in the door closing direction.

In such applications, when negative pressure is applied, the adjustment element 5
It is easily conceivable for the control to be decoupled from the structural part operated in the adjustment direction or to be connected only temporarily to this part.

If this is not possible, the purpose is, for example, to mechanically lock the regulating element 5 during activation of the vacuum (this locking may be directly controlled by the vacuum itself or This is achieved by electrically controlling when the generator is turned on).

However, in the case of special door-closing aids, structural parts which can be moved by the adjusting element and which are rigidly connected thereto can be mechanically restrained directly or indirectly by the door lock until the door is reopened. The adjusting element can be easily locked using the .

In the illustrated embodiment, therefore, the movement of the adjusting element 5 towards the left caused by the application of negative pressure by the dual pump 2 must not at least displace the structural parts (not shown) which can be moved thereby. That is, no mechanical action is performed by the operating element when negative pressure is applied to the operating element.

The control circuit 3 of the dual pump 2 is a push button switch 6
A starting pulse is received by the dual pump 2, and the dual pump 2 is operated to generate positive pressure. Pressure switch 7 in compressed air system 1
After the dual pump 2 has been stopped by the control circuit 3, the dual pump 3 is kept under negative pressure, for example for a predetermined period of time or until the pressure switch 7 issues a corresponding switching signal. Generate operation. The slight adjusting movement of the adjusting element 5 that occurs in that case is not a problem, as mentioned above, but the emptying of the compressed air system 1 temporarily creates a negative pressure in it, which is then condensed. vaporize the water again. The dual pump 2 allows flow to flow through it in the rest state. After this has finally stopped, atmospheric air enters the empty compressed air system 1 through the dual pump 2, and the compressed air system 1 is again at atmospheric pressure.

Structural parts in the other drawings that have the same function as in FIG. 1 are given the same reference numerals as in FIG.

FIG. 2 shows a compressed air system 1' with a plurality of loads 4. In this compressed air system 1', an electric positive pressure bomb 8 and an electric negative pressure bomb 9 are operated by a control circuit 3. Here, the control circuit 3 has a plurality of pulse input terminals 6', and the control circuit 3 has a plurality of pulse input terminals 6'.
The operation of the positive pressure bomb 8 is controlled through. Furthermore, the compressed air system 1' includes electromagnetic 4-boat/2-position switching valves 10 and 3.
A boat/two-position switching valve l1 is arranged between the bombs 8, 9 and the load 4. Both switching valves 10 and 11 are electrically controlled by a control circuit 3. The 4-boat/2-position switching valve 10 connects the negative pressure bomb 9 to either the load 4 or the positive pressure pump 8, and the 3-boat/2-position switching valve l1 connects either the positive pressure bomb 8 or the negative pressure bomb 9. load 4
Connect to. After sufficient pressure has been built up (this is left by the pressure switch 7) and the positive pressure bomb 8 is shut off, the 3-boat, 2-position switching valve 11 is switched by the control circuit 3 and the vacuum pump 9 is switched off. will be introduced for a limited time. As a result, the negative pressure generated in the compressed air system 1' is
Vaporize the condensed water. If necessary, after returning the 3-boat, 2-position switching valve l1 to the inactive state, the 4-boat, 2-position switching valve
The position switching valve 10 is also switched, and a negative pressure is applied to the positive pressure bomb 8 in order to also remove condensed water generated by the positive pressure bomb 8. This process can be carried out each time the load 4 is emptied or also periodically at large time intervals. That time rI
The J1 interval is determined by a humidity sensor or the like which is known per se. Finally, the negative pressure bomb 9 is shut off again, the 4-boat, 2-position switching valve 1o is returned to its rest position, and the compressed air system 1 is short-circuited to the atmosphere through the positive pressure bomb 8 and is again at atmospheric pressure. In order to speed up the emptying of the compressed air system 1, a short-circuit connection via the positive pressure pump 8 is made in order to vent the compressed air system 1' or to expand the air therein to atmospheric pressure level. , also before the negative pressure bomb 9 is switched into operation (for example after the monitoring time interval has elapsed). This reduces the amount of air that must be conveyed by the negative pressure bomb. The load 4 may be, for example, a pneumatic tool to which a positive pressure bomb 8 is inserted as necessary during use. In that case, for example, the existing positive pressure tank is prevented from being emptied and is disconnected from the compressed air system, for example via a non-return valve that is closed during the emptying operation of the compressed air system 1'.

In both of the embodiments described above, even if negative pressure is applied, each compressed air system 1, 1' cannot flow through, but as shown in Figure 3, check valves are installed as far away from the negative pressure generator as possible. This makes it possible to back-flow the compressed air system and thereby suck out the air absorbing the vaporized condensate again. In this embodiment, at least one load 4' is integrated with a schematically illustrated non-return valve 12 which has a throttling effect. Which check valve 12 closes when positive pressure is applied to load 4', but opens when negative pressure is applied. Of course, it can also be installed on the load in any suitable manner. Furthermore, the check valve 12 is configured in a known manner,
It can be made to open only when the negative pressure reaches a predetermined threshold value and to be held in its closed position, for example by an elastic bias pressure. As in the embodiment of FIG. 2, one positive pressure pump 8
and one negative pressure bomb 9 are provided. Here, both bombs 8, 9 are each connected to the compressed air system 1'' via an electromagnetic 2-boat, 2-position switching valve 13, 14, the output ends of these switching valves 13, 14 being connected to the connection point 1.
They are connected to each other by 5. The connection point 15 and the load 4'
A 3-boat/2-position switching valve 16 is provided between the two positions. This switching valve 16 connects the load 4' to the connection point 15 when energized in parallel with the operation of one of the bombs 8 or 9, or when demagnetized, i.e. both bombs 8, 9. connects to the atmosphere when the is at rest. The atmospheric connection of the three-boat, two-position switching valve 16 has an air filter 17 to which a throttle is connected downstream.

Venting or inflating the compressed air system to atmospheric pressure before emptying it, as already mentioned above, ensures that a monitored time interval is maintained between shutting off the positive pressure pump 8 and switching on the negative pressure pump 9. , during which a vent valve can equally easily be carried out by connecting the compressed air system to the atmosphere as described above.

The electrical control of the embodiment shown here is substantially the same as that of the embodiment shown in FIG. 2, and therefore will not be described again here. In this embodiment as well, condensed water can be removed from the positive pressure bomb 8 and the load 4.

The air drying effect of the arrangement in Figure 3 is significantly greater than in the previously described embodiments. This arrangement with a check valve is therefore advantageously employed when a very large amount of condensed water is expected to be produced. Of course, the arrangement shown in FIGS. 1 and 2 can also be equipped with a check valve on the load side. In particular, when arranging the check valve, the check valve should be located as far away from the negative pressure generator as possible in order to ensure as much backflow as possible throughout the compressed air system.

If the load is designed as a piston drive, the check valve can be integrated into the load in a simple manner, since the adjusting piston has a sealing tongue that is actuated from one side.

FIG. 4 shows an embodiment of an adjusting piston with such a sealing tongue. The load 4' with the adjusting element 5, which is designed as a single-acting actuating element, has a cylindrical housing 4.1. A connecting tube 4.2 of this housing 4.1 is connected to a compressed air system (not shown). The adjusting element 5 passes through the housing force bar 4.3 and is drawn out of the housing 4.1. The tube passage in the housing cover 4.3 is sealed off against the adjusting element 5 by a suitable sealing ring 5.1 or by a rolling seal. The adjusting element 5 is mechanically rigidly connected to an adjusting piston 5.2 which is linearly movable within the housing 4.1. The adjusting piston 52 has an annular sealing tongue 5.3. This sealing tongue 5.3 contacts the inner wall of the housing 4.1 when a positive pressure is applied to the connecting tubes 4, 2, and separates from the inner wall in at least six places when a negative pressure is applied. . In that case, the opening threshold value of the "non-return valve" is also determined by its deformation resistance, which is determined by the material and shape of the sealing tongue 5.3. In a simple embodiment, such a seal tongue is used in a bicycle pump. The housing cover 43 is also provided with an outlet hole 20, which is closed by a throttle hole 18 and a flutter valve 19, next to the passageway with the sealing ring 5.1 of the regulating element 5.

The adjusting piston 5.2 has spacing ribs 5, 4 on its side facing the connecting tube 4.2, and a spacing projection 5.5 is provided on the opposite side of the adjusting piston 5.2.

These spacing ribs 5, 4 and spacing projections 5.5 prevent the adjusting piston 5.2 from hitting the bottom of the housing 4.1 in a known manner.

When the regulating piston 5.1 is moved to the right by positive pressure, air can easily escape behind the regulating piston 5.2 through the outlet hole 20 and the flutter valve 19. This allows for greater movement speed. Adjustment piston 5. 2
is biased away from the housing cover 4, 3 with negative pressure, the flutter valve l9 closes the outlet hole 20, so that air enters the chamber behind the adjusting piston 5.2 only through the throttle hole l8. In this case, a slow backflow is possible through the throttle hole 18 and past the sealing tongue 5.1 towards the connecting tube 4.2. The spacing rib 5.4 is connected to the adjusting piston 5.2
is also in contact with the left-hand bottom of the housing 4.1, allowing its backflow. At the same time, this seal tongue piece 5.
3 and the bottom of the housing 4.1 is prevented.

The negative pressure necessary to vaporize the condensed water is created by strongly throttling the reverse flow in the restrictor hole 18. When employing such operating elements in highly contaminated environments,
Instead of a simple narrow throttle hole, a cylindrical hole is provided in which a sintered body throttle is fitted, which also acts as an air filter.

Of course, the invention is not limited to the use of the piston type drive device described above. The present invention can be employed in many places in compressed air systems where reverse flow through the system is desired.

[Brief explanation of drawings]

Figure 1 is a schematic system diagram of a compressed air system with dual pumps that can sufficiently remove condensed water, and Figure 2 shows that condensed water is removed from the positive pressure generator and load by a separately installed negative pressure generator. A schematic system diagram of a compressed air system that can remove the condensed water, FIG. FIG. 4 is a sectional view of the actuating element/piston drive with a sealing tongue acting as an integral check valve. 1...Compressed air system, 2...Dual pump, 3.
...Control device, 4.Load, 5.Adjustment element, 7.
...Pressure switch, 8...Positive pressure bomb, 9...Negative pressure bomb, 11...Switching valve, 12...Check valve, 13
, l4... switching valve, 18... throttle hole.

Claims (15)

[Claims] (1) A compressed air system of a motor vehicle which can be alternately energized with positive air pressure and is subjected to atmospheric pressure in the rest state, especially when at least one load which can also be energized with negative pressure and which performs a mechanical action by the energization of positive pressure. In a method for removing condensate from a compressed air system for a pneumatic door closing aid having at least one time interval, the compressed air system is emptied immediately after energizing positive pressure, and at least one load is mechanically operated. A method for removing condensate from a compressed air system, characterized in that it does not perform any action. 2. A method as claimed in claim 1, characterized in that immediately after energizing the at least one load with positive air pressure, the compressed air system is emptied at atmospheric pressure before going to rest. 3. Process according to claim 1, characterized in that the removal of condensate water is assisted by a restricted backflow of the evacuated compressed air system. (4) Reversible pressure generators In particular in methods where dual pumps are used, the pressure generator for emptying the compressed air system is switched by an electrical control device to generate positive pressure immediately followed by negative pressure generation. Claim 1 characterized in that
Or the method described in 2. (5) The air present in the compressed air system is expanded after application of positive air pressure and before being emptied by connecting the compressed air system to the atmosphere. The method described in any one of . 6. The method of claim 5, wherein a predetermined monitoring time interval is maintained between the end of positive pressure application and the start of emptying the compressed air system. (7) A pressure generator formed as a reversible dual pump (2) used to generate positive pressure and negative pressure, and a pressure generator connected to this pressure generator via piping and powered by positive pressure. compressed air system of a motor vehicle, in particular for pneumatic door closing aids, in which a positive air pressure can be applied alternately and atmospheric pressure is applied in the rest state, with at least one load having an actuating effect; 2. A device for carrying out the method according to claim 1 for removing condensate from an air system, characterized in that the compressed air system (1) is emptied in a timed manner after each positive pressure generated by the dual pump (2). The control circuit (3) of the dual pump (2) switches to negative pressure generation operation for
), dual pump (
said control circuit ( 3) The compressed air system (
1, 1') and at least one single-acting drive type load (4) which performs a mechanical action exclusively when energized with positive pressure. Device. (8) A device having a positive pressure generator, a negative pressure generator, and at least one load that can be coupled to the positive pressure generator and the negative pressure generator and performs a mechanical action by biasing the positive pressure. 2. A method according to claim 1 for removing condensate from a compressed air system of a motor vehicle, in particular a compressed air system for a pneumatic door closing aid, which can be alternately energized with positive air pressure and is subjected to atmospheric pressure in the rest state. A control circuit (3) for electrically operating the positive pressure generator (8) and the negative pressure generator (9) independently of each other, and a compressed air system (1', 1''). The control circuit (3) for alternately connecting the
) electrically controlled switching devices (11, 13, 1
4), when a predetermined positive pressure threshold is reached, the positive pressure generator (8
) for generating an electrical pressure threshold signal which is introduced into said control circuit (3) for switching off the switching devices (11, 13, 14) and switching on the negative pressure generator (9). a pressure switching device (7) in the compressed air system (1', 1'') electrically connected to said control circuit (3) and at least one single-acting drive with mechanical action exclusively when energized with positive pressure; A device characterized in that it has a load (4) of the formula: (9) at least one check valve (12, 5.3) located away from the negative pressure generator (9) and close to the load, which check valve Device according to claim 7 or 8, characterized in that it allows (1") of reverse flow through. (10) has a vent valve (16) for the compressed air system (1'') switched by the control circuit (3), which vent valve compresses air in parallel with the operation of the pressure generator (2, 8, 9); Device according to any one of claims 7 to 9, characterized in that it is switched into a position separating the air system (1") from the atmosphere, and in the rest position connects the compressed air system (1") to the atmosphere. . 11. Device according to claim 9, characterized in that it has at least one non-return valve (12, 5.3) integrated in the compressed air load. (12) Housing (4.1) and connecting short pipe (4.2)
) at least one compressed air load (4) designed as a piston adjustment device with an adjustment piston (5.2
) and the inner wall of the housing (4.1).
2), which has a sealing tongue (5.3) acting as Aperture hole (1
12. Device according to claim 11, characterized in that 8) is opened. (13) at least one compressed air load housing (
13. Device according to claim 12, characterized in that 4.1) is provided with an outlet hole (20) parallel to the throttle hole (18), which outlet hole (20) can be closed by a flutter valve (19). (14) A device according to claim 12 or 13, characterized in that the aperture (18) is largely narrowed. (15) The device according to claim 12 or 13, characterized in that the throttle hole is fitted with a sintered body throttle for purifying the backflow throughflow air.